Automatic Air Vents

[Diggory]

I’m in process of replacing my old vented system with new combi system.
The old original system had a couple of auto air vents on the 22mm flow/returns in loft.
They don’t look in great shape so need replacing or deleting.

By the time I’m finished the 22mm flow/returns will be all the remains of the original system.
What’s the consensus on needing/keeping these auto vents on a new sealed system.

Thanks D

 

[Madrab]

If they are in the loft it will be because that's the highest part of the system and without the AAV's then it could create airlocks @ those points.

If the pipes in the loft are being retained then the vents may still be needed. Even if you go sealed, any air that may enter the system will still find its way up there and could cause circulation issues.

If they are the bottle type vents then they seem to leak just for laughs, I always fit Flamco Flexvents, they seem to be much more reliable

 

[Diggory]

Thank you - that’s very helpful and with a recommendation .

I’ll check the existing vents this afternoon……..
I’ve a feeling that the 22mm flow/returns may have a ‘reducing tee’ and short vertical of 15mm before AAVs.
I’m guessing I’d need the 1/2” AAVs - like these ?

Thanks again D

 

[Madrab]

Either or and if they are already set on 15mm tails then yes the 1/2" vents would do, just need a 1/2" female compression adapter to fit.

 

[oilhead]

As they are at the highest point, it will be worth keeping them as vents, , but I would replace them with manual vents. You may find that they have a tendency to allow air to enter at some times when the circuit is flowing and the seats will deteriorate causing more loss and requiring constant topping up.

 

[Diggory]

I would replace them with manual vents

That’s an interesting idea - something like this ?
And then bleed them as and when like I would the highest radiator ?

D

 

[Diggory]

I’ll retain the high point air bleeds - thank you @Madrab

I would replace them with manual vents

Just checking I’ve understood (@oilhead )
Because the Auto-vents are so unreliable, a safer bet is to install simple manual vents.
So I’m thinking I could cut off the bottle vents and use either this or this.
Is it sensible to incorporate a 90deg elbow so vents are horizontal ?
(to get a receptacle under them to catch water when bleeding)

Thanks D

 

[Diggory]

Thanks for advice.
Removed / replaced the aged auto valves.

D

 

[Madrab]

Ah, they were already Flamcos, doesn't look like they've leaked though, just a bit of surface corrosion probably from condensation.

 

[Johntheo5]

Some now I believe can be removed for cleaning without drain down or the need for a isol valve, like a lot of shower filters which can also be removed without isolation.